Why liquid hydrogen is still being pursued as a long-distance H2 carrier, despite its limitations and high costs
LH2 shipments could work out cheaper than ammonia for importing countries with high energy prices, senior Kawasaki Heavy Industries executive tells conference
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So why haven’t shipbuilder Kawasaki Heavy Industries and the Japanese government pulled the plug on their (heavily subsidised) development of a “commercial-scale” liquid hydrogen carrier within the next two to three years?
“Every solution has good points and bad points,” began Toshihisa Doi, managing director for Kawasaki Heavy Industries in the Middle East, speaking at the Connecting Green Hydrogen MENA conference in Dubai this week.
A short history of international liquid hydrogen shipments
Kawasaki Heavy Industries completed construction of the world's first liquid-hydrogen (LH2) carrier, the Suiso Frontier, albeit without any storage tanks, in Japan in December 2019, as part of the $359m Hydrogen Energy Supply Chain (HESC) pilot project.
Its 1,250-cubic-metre vacuum-insulated LH2 storage tank was installed in March 2020, but it took until July 2021 for the storage equipment to be given approval-in-principle by Japanese classification society ClassNK, partly due to the fact that foreign engineers were unable to travel to Japan due to the Covid pandemic.
The vessel finally set sail from Australia to Japan with the world's first international shipment of LH2 (made from unabated brown coal) in January 2022. It emerged months later that one-metre flames were seen on deck when it was still stationed at the Australian port of Hastings — prompting an investigation by the Australian Transport Safety Bureau into the 'serious incident'.
The government agency finally concluded in February 2023 that an incorrectly fitted valve and an ineffective automated safety system caused the flames, which occured when the ship's gas combustion engine was switched on to burn LH2 boil-off gas (ie, the small proportion of the stored hydrogen that gasifies when it reaches boiling point [minus-253°C] due to warmer temperatures outside the tank).
Nevertheless, the trial was deemed a success and in March last year, the Japanese government earmarked ¥220bn ($1.6bn) to the HESC consortium for a follow-up commercial-demonstration project to ship 30,000 tonnes a year of hydrogen (made from brown coal with carbon capture) from the Port of Hastings to Japan.
In May 2022, Kawasaki announced that the design for a new long-distance LH2 carrier with 160,000 cubic metres of LH2 storage capacity had been given technical approval by ClassNK. But the Japanese shipbuilder continued to work on an LH2 cargo containment system, with technical development only being completed in June 2023, with no further information forthcoming since then.
And in April 2023, French oil major TotalEnergies announced that it was designing an LH2 carrier with 150,000 cubic metres of storage in conjunction with naval architect LMG Marin, gas technology provider GTT and classification society Bureau Veritas (BV).
That design was given approval-in-principle by BV in February this year.
So to date, the only LH2 carrier built to date is the Suiso Frontier, but it was never intended to be a commercially viable vessel.
For example, ammonia can be transported “very easily” as a liquid at temperatures below minus-33°C, or at ambient temperatures with a little compression (7.5 bar at 20°C) — and if the end users want to use this ammonia directly, “there’s no problem”.
“But if the final user wants hydrogen, for the fuel cell, we need to extract that hydrogen from ammonia,” he said. “At the importing country, like Japan or Korea, the energy price is very high.”
As such, he expects the final price of hydrogen if ammonia or liquid organic hydrogen carriers (LOHCs) are used as a carrier “will be increased” because high-cost electricity is needed to extract the H2 from those chemicals.
He also said that both ammonia and methylcyclohexane, a commonly proposed LOHC in Japan, are toxic chemicals. “It’s a bit difficult to handle,” he adds — which could mean extra costs to ensure health and safety.
Meanwhile, for hydrogen to reach a liquid state, it must be cooled to minus-253°C, which Doi conceded is “very difficult technologically”, with high energy consumption at the point where it is liquefied.
“There’s a lot of energy for liquefaction, but usually exporting countries, maybe Saudi [Arabia] or others, energy prices are not really high — so economically, it’s not a big deal,” he argued.
While the IEA’s analysis supports Doi’s view that energy costs for reconverting hydrogen from liquid to gas are negligible, particularly compared to ammonia or LOHCs, the agency also calculated that storage tanks will account for more than $1/kg of the $2-2.50/kg indicative levelised cost of transporting liquid hydrogen by 2030.
Meanwhile, the cost of storage tanks for ammonia and LOHCs appears to be less than half those for liquid hydrogen due to their higher density by volume — contributing to lower costs, regardless of distance, the IEA found.
However, it is unclear how the IEA estimated its modelled energy costs at the export and import terminal, although the report did note that “hydrogen liquefaction benefits from lower energy costs at the export terminal”.
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